1. Field of the Invention
The invention relates to the field of digital audio recording and, more specifically, to a method for synchronously operating two or more digital audio tape recorders.
2. Description of the Prior Art
In professional digital audio applications, it is often desirable to be able to operate two or more rotary head digital audio recording machines synchronously. During synchronous operation, each recorder is precisely lined up on an exact sample per sample basis. Synchronous operation of multiple rotary head digital audio recorders permit a user to increase the number of available recording tracks by combining the multi-track capability of several recorders. Instead of requiring a more expensive sixteen track recorder, for instance, a user could synchronously operate two eight track rotary head recorders.
During synchronous operation, it is convenient to be able to operate the digital audio recorders in a variety of different modes of operation, such as playback, record, and high-speed scanning (both forward and backward). During normal operation, the rotary head is capable of detecting all of the information stored on the magnetic tape. However, in a high-speed scan, or "shuttle" mode, the linear tape speed is increased while the rotational speed of the rotary head is kept constant. Thus, not all information can be detected.
It is desirable to provide synchronous operation of the rotary head recorders during normal operation to within single sample accuracy. This allows the master and slave recorders to operate with a precise timing relationship to one another at normal operating speeds.
In the prior art, when multitrack recorders are "ganged" together to operate synchronously, one track of the master recorder is dedicated to providing synchronizing information to the slave recorders. Track dedication eliminates a potential recording track that could be used to record a digital audio information. Using the prior art, if two eight track digital audio recorders are operated synchronously, one track is dedicated to synchronizing information, leaving only fifteen digital audio recording tracks. Thus, to provide sixteen track capability in the prior art, three eight track digital audio recorders have to be used. This is both inconvenient and inefficient.